1. Field of the Invention
The present invention relates to a Light Emitting Diode (LED) module for a line light source and, more particularly, to an LED module for a line light source, which increases light emission efficiency and maximizes heat radiation capacity.
2. Description of the Related Art
In general, LED chips are semiconductor devices made of compound materials such as GaAs, AlGaAs, InGaAs, GaN, InGaN, etc. and configured to emit various colors of beams. The LED chips are used in the form of packages, which can be used as light sources for planar displays using liquid crystal displays, etc.
FIG. 1 is a sectional view illustrating a conventional LED module.
Referring to FIG. 1, the conventional LED module 10 is fabricated in the form of a Surface Mount Device (SMD), and includes a Metal Core Printed Circuit Board (MCPCB) 12, a wire pattern 14 formed on the MCPCB, and an LED package 16 electrically connected to the wire pattern.
The MCPCB 12 supports the LED package 16 and controls the light emission of the LED package 16 with a circuit connected to the package.
The LED package 16 includes a package body 16a, an LED chip 16b mounted on the package body 16a, and a resin encapsulant 16c sealing the LED chip 16b. Here, the LED chip 16b is a point light source generating red, green or blue light, and the red, green and blue LED chips 16b can be combined to obtain white light from the LED module 10.
However, the LED module with the above structure is not effective in radiating heat from the LED chip due to the low heat radiation capacity of the MCPCB, and when the heat remains in the package without being radiated, light efficiency is degraded.
In addition, the LED package occupies a large space, hindering miniaturization, and the LED chip should be attached by a reflow process, which increases the costs.
FIG. 2a is a schematic view illustrating the LED module of FIG. 1 applied as a backlight unit, and FIG. 2b is a picture showing the light emission characteristics of the backlight unit.
In general, a beam angle of the LED package 16 used in the conventional LED module cannot be adjusted greater than maximum ±120°. Thus, as shown in FIGS. 2a and 2b, a dark spot 30 is formed in a portion of a light guide plate 20 where a relatively smaller amount of light reaches, and such a dark spot 30 degrades the uniformity of the luminance of the liquid crystal display.
Furthermore, the conventional LED module is not effective in preventing the loss of light emitted in lateral directions, further degrading the luminance.